* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
html,body {
    width: 100%;
    height: 100%;
    background: url(../images/index_bg.png) no-repeat;
    background-size: 100% 100%;
}
.box {
    width: 100%;
    height: 100%;
    display: flex;
    .left-box {
        width: 25%;
        height: 100%;
        background-color: beige;
    }
    .content-box {
        width: 50%;
        height: 100%;
        background-color: blueviolet;
    }
    .right-box {
        width: 25%;
        height: 100%;
        background-color: brown;
    }
}
